Plastiome: Plastisphere-enriched mobile resistome in aquatic environments

Aquatic microplastics (MPs) act as reservoirs for microbial communities, fostering the formation of a mobile resistome encompassing diverse antibiotic (ARGs) and biocide/metal resistance genes (BMRGs), and mobile genetic elements (MGEs). This collective genetic repertoire, referred to as the “plastiome,” can potentially perpetuate environmental antimicrobial resistance (AMR). Our study examining two Japanese rivers near Tokyo revealed that waterborne MPs are primarily composed of polyethylene and polypropylene fibers and sheets of diverse origin. Clinically important genera like Exiguobacterium and Eubacterium were notably enriched on MPs. Metagenomic analysis uncovered a 3.46-fold higher enrichment of ARGs on MPs than those in water, with multidrug resistance genes (MDRGs) and BMRGs prevailing, particularly within MPs. Specific ARG and BMRG subtypes linked to resistance to vancomycin, beta-lactams, biocides, arsenic, and mercury showed selective enrichment on MPs. Network analysis revealed intense associations between host genera with ARGs, BMRGs, and MGEs on MPs, emphasizing their role in coselection. In contrast, river water exhibited weaker associations. This study underscores the complex interactions shaping the mobile plastiome in aquatic environments and emphasizes the global imperative for research to comprehend and effectively control AMR within the One Health framework. Antimicrobial resistance (AMR) poses a growing global pandemic as microbes evolve to develop drug resistance. Aquatic microplastics (MPs) act as reservoirs for pathogenic microbes, nurturing a mobile resistome encompassing diverse antimicrobials and metal resistance genes. This collective genetic repertoire, referred to as the “plastiome,” can potentially perpetuate environmental AMR. Our investigation in two Japanese rivers reveals robust associations between host genera and resistant genes on MPs. This research underscores the crucial role of the mobile plastiome in aquatic environments, influencing environmental AMR, and emphasizes the need for global studies to comprehend and control AMR associated with the plastiome.